Question #25:
One way to solve this is by multiplying the number of packages per serving by the number of guests.
1/4 * 16 = 4 packages to serve 16 guests. This means he doesn't have enough.
A second way to solve this is by diving the number of packages by the number of packages it takes to make on serving.
3 1/2 ÷ 1/4 = 14 guests he can serve. This means he doesn't have enough.
Question #26:
First, find common denominators.
2/3 = 8/12
1/4 = 3/12
Second, subtract.
8/12 - 3/12 = 5/12
Therefore, the tank is 5/12 full at the end of the trip.
Question #27:
1/2 is cut off then 1/3 is cut off. This means 3/6 was cut off to bundle newspapers, then 1/6 was cut off to make parcel. In all, 4/6 was cut off the original string. Afterwards, 2/6 was left over. So, just multiply; 2 * 3 = 6.
Therefore, the original string was as a total of 6 meters.
Hope this helps! :)